Telephonic receiver for wireless signal apparatus.



No. 700,|6I. 'Patented May 13, I902.

' T. TOMMASINA.

TELEPHONIG RECEIVER FOR WIRELESS-SIGNAL APPARATUS.

(Application filed May 24, 1900;)

III

(No Model.)

In Er Tu: uomus was no. FKOYO-LITKO. WASHINGTON a. c.

UNITED STATES PATENT FF-ICE'.

THOMAS TOMMASINA, OF GENEVA, SWITZERLAND, ASSIGNOItTOPAUL :GALOPI N, OF GENEVA, SWITZERLAND.

TELEPHONIC RECEIVER FOR VV IRELESS SIGNAL APPARATUS.

SPECIFICATION formingpart of Letters Patent No. 700,161, dated May 13, 1902.

Application filed May 24, 1900.

T0 Ml whom, it may concern:

Be it known that I, THOMAS TOMMASINA, of. Geneva, Switzerland, have invented an Im'- proved Tele'phonic Receiver for Wireless Sig-.

nal Apparatus, of which the following is a.

specification.

My invention relates to a telephonic-re ceiver for wireless signal apparatus for Hertz-- zian rays, which may be called a coherertelephone, and in carrying out my invention. I employ. a telephone-receiver and providev the diaphragm thereof with a cohererwhich' is connected electrically to suitable terminals on the receiver, said terminals being connect. ed, respectively, to the air-line and ground;-

and which also act as terminals for a relay-circuit, the latter circuit controlling a second circuit in which the electromagnet of the telee phone-receiver and a recording apparatus are connected, so that the relay-circuit is closed through the coherer by the Hertzian rays passing through the same from the air-line to ground, and the said second circuit is closed in turn by the relay to operate the recording apparatus and energize the magnet to operate the receiver-diaphragm, producing a' sound and at the same time discohering the cohering material of the coherer. The sound produced by the receiving instrument is sufficiently loud to be heard distinctly without placing the instrument to the ear, and hencein use it is not necessary to remove the instrument from its hook or other similar means of support.

The accompanying drawings show, by way of example, one construction of the instrument.

Figure 1 is an axial section of the same with diagrammatical indication of the electrical circuit. Fig. 2 is an under side view of Fig.

1.- Fig. 3 shows in section another form of membrane.

For better understanding of the drawings the thickness of the parts forming the membranes is exaggerated. I

a is the electromagnet, the binding-posts r ands of which are connected in a circuit comprising a battery, a relay, and any suitable registering apparatus 3for instance,a Morse receiver. b is the. iron diaphragm of the ordinary tele- Serial No. l 7,7 8 8. (No model.)

phonic receiver, one face of which iscovered with asheet of insulating material 0, such as paper; on which is fixed, by means .of. a second sheet of insulating material d, a plate of insulating material e, having an opening f,

formin g the recess in which the cohering powder (metallic filings, carbon powder, 850.) is lodged.

I -g isa sheet of mica closing the recess, .al-

'lowing the cohering powder, however, to be I observed.

h and erably made of silver and which form the electrodes intended to be temporarily connected by the cohering powder when acted upon by the Hertzian' rays. It will be easily understood that on the one hand the l-Iertzian rays acting upon the aerial conductor and by means of the same upon the circuit formed by the conductors h andz' close the circuit by their cohering action upon the cohering powder and act upon the signalregistering apparatus by means of the relay 2, which closes" the circuit of the battery 1, and at the same time the current sent through the electromagnet a produces the rising and falling of the membrane, from which results the necessary mechanical shaking to discohere the cohering powder. i In the form represented in Fig. 3 the membrane 7c is made of insulating material and carries an iron plate-Z, fixed by means of a paper covering .f and intended .to work as the armature of the electromagnet e. In the membrane itself is formed a cavity m, containin g the cohering powder and in which the electrodes at and 0 (which in this case are formed of two sheets of silver connected to the wires h and t') terminate.

p and q are sheets of mica closing the cavity.-

The case of the electrom agnet is generally made of iron not magnetized. The space between the electrodes and the electromagnet must'be greater than five millimeters if it be desired to have a loud sound and a little less if a weaker sound is sufficient. Besides, the distance depends on the power of the current of the battery 1 and on the size ,ot the electromagnet and also on the sensibility of the apparatus.

The characteristic feature of my invention '6 are two metallic conductors, pref'- is that the eoherer is fixed to the vibrating membrane of a telephone receiver. With this quite new construction one may practically obtain by merely exchanging the cohering powder and without changing any other portion of the apparatus two different results, as follows:

First. If the cohering powder supplied in the apparatus is made of non-magnetic metal or of a combination of non-magnetic metals, as gold, silver, platinum, or the like, the receiver will be very sensitive and be liable to be acted upon at great distance. The same will then be connected with a relay 2, and the signals will be transmitted to a recording apparatus 3, as shown in the drawings.

Second. If the cohering powder supplied in the apparatus is made'of magnetic metal or of a combination of magnetic metals, (nickel, cobalt, iron, steel,) the receiver will be somewhat less sensitive, but it will work with more precision because of the magnetic action of the electromagnet upon the eoheringpowder, which magnetic action aids the mechanical shaking action of the said electromagnet for diseohering the cohering powder. This double discohcring action prevents any error in the transmission of signals. The apparatus will again be connected with a relay 2 and the signals be transmitted to a recording apparatus 8, as shown in the drawings.

The cavity containing the cohering powder may be in the center of the membrane or concentric to it, and it may be of regular section, square, orrectangularofsuitable dimensions.

The electrodes in contact with the cohering powder may be of plain metallic Wires or of thin blades of silver or other metal forming continuation of the wires or fixed side by side of the disk, leaving between each a fraction ofa millimeter. This distance also must vary according to the sensitiveness that is given to the apparatus. The larger this distance is the less sensitive the apparatus will be, whatever may be the form or the substance of the electrodes in contact with the cohering powder. Similarly the size and quantity of said cohering powder, and consequently the size of the cavity, is inversely as the sensitiveness. Both conductor-wires terminate at two binding-posts laterally to the cover of the telephone, to which are connected the two ends of the circuits of the battery 1 containing the relay 2. This relay is intended to close the circuit of the eleetromagnct a, in which are inserted the battery 1 and the recording apparatus 3. The aerial wire it and the earth-wire 'v are also connected with the ends of the same contacts 7L and '5.

I claim as my invention 1. In a telephonic signal-receiving apparatus for Hertzian rays, the combination with the electromagnet employed therein, of an armature, a disk of insulating material 0011- neeted to but insulated from said armature and having a recess therein, cohering powder retained in said recess, electrical conductors in contact with said cohering powder and binding-posts to which their ends are connected, an electric circuit with terminals connected to the electromagnet, a relay and an electric circuit in which the relay is embraced with terminals connected to the binding-posts, and an aerial line and a line to ground also connected to said binding-posts substantially as and for the purposes specified.

2. In a telephonic signal-receivingapparatus for Hertzian rays, the combination with the eleetromagnet employed therein, of a movable diaphragm comprising the armature of the eleetromagnet, a disk of insulating material provided with a centrally-placed recess and connected to and insulated from the said diaphragm, metallic cohering powder placed within said recess and means for retaining the same therein, electrical conductors in contact with said cohering powder, binding-posts to which the ends of said conductors are secured, an aerial wire connected to one binding-post and a ground connection to the other binding-post, a battery, a relay, and electrical connections comprising a circuit whose terminals are said binding-posts, a battery and a recorder in circuit with the electric magnet and which circuit is closed by said relay, sub' stantially as and for the purpose set forth.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

THOMAS TOMMASINA. 

